Effects of Buffer Strips and Grazing Management on Edge of Field Soil Loss from Pastures.

Intense grazing pressure by cattle can lead to soil erosion in pastures causing increased soil loss into nearby waterways. The objectives of this study were to determine the long-term impact of grazing management and buffer strips on soil erosion by assessing soil physical properties, hydrology, and sediment loads from pastures fertilized with poultry litter. This research was conducted for 12 years on 15 small watersheds in which five management strategies were evaluated; hayed (H), continuously grazed (CG), rotationally grazed (R), rotationally grazed with a buffer strip (RB), and rotationally grazed with a fenced riparian buffer (RBR). Poultry litter was applied annually in spring at a rate of 5.6 Mg ha^-1. Penetration resistance and bulk density of surface soil increased as grazing pressure increased and was highest for CG watersheds. Runoff volumes, sediment concentrations and sediment loads were also highest for CG and were lowest for H and RBR watersheds.  The average annual runoff amounts were 4.8, 8.4, 7.7, 6.0, and 8.1 cm yr^-1 for the H, R, RB, RBR, and CG treatments, respectively. Annual average TSS loads were 25, 30, 58, 71, and 110 kg ha^-1 for H, RBR, R, RB, and CG, respectively.  RUSLE2 (Revised Universal Soil Loss Equation, Version 2) did a fairly good job at predicting soil loss for the R, RB, and RBR treatments, but overpredicted soil loss from CG and H treatments. Converting pastures to a hay fields or using rotational grazing in conjunction with a fenced riparian buffer strip appear to be the best options for reducing soil erosion and runoff to waterways.